[PATCH net-next v4 06/14] ibmveth: Refactor TX resource allocation in open/close paths

Same story as the RX refactor: pull TX LTB alloc/free out of open/close
into helpers and wire them in this patch.

  ibmveth_alloc_tx_resources()
  ibmveth_free_tx_resources()

They wrap the existing per-queue allocate_tx_ltb() / free_tx_ltb()
primitives. alloc_tx_resources() allocates every TX queue and unwinds
partial failure itself; free_tx_resources() walks real_num_tx_queues.
TX was already multi-queue capable via ethtool -L, so there is no MQ
RX behaviour change here.

Also tighten TX LTB lifetime: free_tx_ltb() is safe on an unallocated
slot and clears tx_ltb_dma[] after unmap; allocate_tx_ltb() clears
tx_ltb_dma[] after DMA-map failure.

Move TX LTB allocation to the end of open(), after LAN registration,
RX pools, RX interrupt setup, and the initial replenish kick. A late
alloc_tx_resources() failure jumps to out_cleanup_rx_interrupts and
must not call free_tx_resources() again: alloc already freed any
partial TX LTBs. That also retires a mid-open TX leak where the old
index-based while (--i) free could skip successfully allocated LTBs.

close() uses free_tx_resources() and cleanup_rx_interrupts().

Signed-off-by: Mingming Cao <[email protected]>
Reviewed-by: Dave Marquardt <[email protected]>
Tested-by: Shaik Abdulla <[email protected]>
---

Changes in v4:
- Introduce the TX resource helpers in the same patch that wires their
  first open/close callers.
- Do not free TX LTBs again after a failed alloc_tx_resources();
  harden free_tx_ltb() against unset slots.
- Move TX allocation after RX IRQ setup / replenish kick so open()
  failure unwind no longer depends on a shared loop index (also fixes
  a mid-open TX LTB leak).

 drivers/net/ethernet/ibm/ibmveth.c | 90 ++++++++++++++++++++++--------
 1 file changed, 66 insertions(+), 24 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index 664169c4d27a..131c1a61d9e7 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -1077,8 +1077,14 @@ static int ibmveth_rxq_harvest_buffer(struct ibmveth_adapter *adapter,
 
 static void ibmveth_free_tx_ltb(struct ibmveth_adapter *adapter, int idx)
 {
-	dma_unmap_single(&adapter->vdev->dev, adapter->tx_ltb_dma[idx],
-			 adapter->tx_ltb_size, DMA_TO_DEVICE);
+	if (!adapter->tx_ltb_ptr[idx])
+		return;
+
+	if (adapter->tx_ltb_dma[idx]) {
+		dma_unmap_single(&adapter->vdev->dev, adapter->tx_ltb_dma[idx],
+				 adapter->tx_ltb_size, DMA_TO_DEVICE);
+		adapter->tx_ltb_dma[idx] = 0;
+	}
 	kfree(adapter->tx_ltb_ptr[idx]);
 	adapter->tx_ltb_ptr[idx] = NULL;
 }
@@ -1101,12 +1107,54 @@ static int ibmveth_allocate_tx_ltb(struct ibmveth_adapter *adapter, int idx)
 			   "unable to DMA map tx long term buffer\n");
 		kfree(adapter->tx_ltb_ptr[idx]);
 		adapter->tx_ltb_ptr[idx] = NULL;
+		adapter->tx_ltb_dma[idx] = 0;
 		return -ENOMEM;
 	}
 
 	return 0;
 }
 
+/**
+ * ibmveth_alloc_tx_resources - Allocate TX resources for all queues
+ * @adapter: ibmveth adapter structure
+ *
+ * Allocates TX Long Term Buffers (LTBs) for all TX queues.
+ *
+ * Return: 0 on success, -ENOMEM on failure
+ */
+static int ibmveth_alloc_tx_resources(struct ibmveth_adapter *adapter)
+{
+	struct net_device *netdev = adapter->netdev;
+	int i;
+
+	for (i = 0; i < netdev->real_num_tx_queues; i++) {
+		if (ibmveth_allocate_tx_ltb(adapter, i))
+			goto err_free_ltbs;
+	}
+
+	return 0;
+
+err_free_ltbs:
+	while (--i >= 0)
+		ibmveth_free_tx_ltb(adapter, i);
+	return -ENOMEM;
+}
+
+/**
+ * ibmveth_free_tx_resources - Free TX resources for all queues
+ * @adapter: ibmveth adapter structure
+ *
+ * Frees TX Long Term Buffers (LTBs) for all TX queues.
+ */
+static void ibmveth_free_tx_resources(struct ibmveth_adapter *adapter)
+{
+	struct net_device *netdev = adapter->netdev;
+	int i;
+
+	for (i = 0; i < netdev->real_num_tx_queues; i++)
+		ibmveth_free_tx_ltb(adapter, i);
+}
+
 static int ibmveth_register_logical_lan(struct ibmveth_adapter *adapter,
         union ibmveth_buf_desc rxq_desc, u64 mac_address)
 {
@@ -1157,12 +1205,6 @@ static int ibmveth_open(struct net_device *netdev)
 	if (rc)
 		goto out_free_filter_list;
 
-	rc = -ENOMEM;
-	for (i = 0; i < netdev->real_num_tx_queues; i++) {
-		if (ibmveth_allocate_tx_ltb(adapter, i))
-			goto out_free_tx_ltb;
-	}
-
 	mac_address = ether_addr_to_u64(netdev->dev_addr);
 
 	rxq_desc.fields.flags_len = IBMVETH_BUF_VALID |
@@ -1184,35 +1226,38 @@ static int ibmveth_open(struct net_device *netdev)
 				     rxq_desc.desc,
 				     mac_address);
 		rc = -ENONET;
-		goto out_free_tx_ltb;
+		goto out_free_queue_mem;
 	}
 
 	rc = ibmveth_alloc_buffer_pools(adapter);
 	if (rc)
-		goto out_free_tx_ltb;
+		goto out_unregister_lan;
 
 	rc = ibmveth_setup_rx_interrupts(adapter);
-	if (rc) {
-		do {
-			lpar_rc = h_free_logical_lan(adapter->vdev->unit_address);
-		} while (H_IS_LONG_BUSY(lpar_rc) || (lpar_rc == H_BUSY));
-		goto out_free_buffer_pools;
-	}
+	if (rc)
+		goto out_unregister_lan;
 
 	netdev_dbg(netdev, "initial replenish cycle\n");
 	ibmveth_schedule_rx_queue(adapter, 0);
 
+	rc = ibmveth_alloc_tx_resources(adapter);
+	if (rc)
+		goto out_cleanup_rx_interrupts;
+
 	netif_tx_start_all_queues(netdev);
 
 	netdev_dbg(netdev, "open complete\n");
 
 	return 0;
 
-out_free_buffer_pools:
+out_cleanup_rx_interrupts:
+	ibmveth_cleanup_rx_interrupts(adapter);
+out_unregister_lan:
+	do {
+		lpar_rc = h_free_logical_lan(adapter->vdev->unit_address);
+	} while (H_IS_LONG_BUSY(lpar_rc) || (lpar_rc == H_BUSY));
 	ibmveth_free_buffer_pools(adapter);
-out_free_tx_ltb:
-	while (--i >= 0)
-		ibmveth_free_tx_ltb(adapter, i);
+out_free_queue_mem:
 	ibmveth_cleanup_rx_resources(adapter);
 out_free_filter_list:
 	ibmveth_free_filter_list(adapter);
@@ -1224,13 +1269,13 @@ static int ibmveth_close(struct net_device *netdev)
 {
 	struct ibmveth_adapter *adapter = netdev_priv(netdev);
 	long lpar_rc;
-	int i;
 
 	netdev_dbg(netdev, "close starting\n");
 
 	netif_tx_stop_all_queues(netdev);
 
 	/* PHYP mask + napi_disable + free_irq live in cleanup_rx_interrupts */
+	ibmveth_free_tx_resources(adapter);
 	ibmveth_cleanup_rx_interrupts(adapter);
 
 	do {
@@ -1248,9 +1293,6 @@ static int ibmveth_close(struct net_device *netdev)
 	ibmveth_cleanup_rx_resources(adapter);
 	ibmveth_free_filter_list(adapter);
 
-	for (i = 0; i < netdev->real_num_tx_queues; i++)
-		ibmveth_free_tx_ltb(adapter, i);
-
 	netdev_dbg(netdev, "close complete\n");
 
 	return 0;
-- 
2.50.1 (Apple Git-155)